Abstract:
A tria lw as estab lished in 1999 in Lechang, Guangdong, wh ich inc luded 17 hybrid fam ilies o fP inus elliottii var. elliottii( PEE ) by P. caribaea var. hondurensis ( PCH ), 4 hybrid fam ilies o f PEE by P. caribaea var.bahm ensis( PCB ), 9 PEE open-po llina ted fam ilies( PEE ( op) ) and 1 PCH open-po llinated fam ily ( PCH ( op) ), aswell as 8 seedlots from pine seed orchards in Guangdong prov ince. These seed o rchardsw ere primary PEE seed o rchard( PEE ( p) ) in T aishan, first-generat ion PEE orchard ( PEE ( o) ) in Ta ishan, improved PEE seed o rchards( PEE ( i) ) in Ta ishan, pr imary P. caribaea var. caribaea seed orchard( PCC ( p) ) in Zhanjiang, primary PCB seedorchard( PCB ( p) ) in Zhan jiang, prim ary PCH seed orchard( PCH ( p) ) in Zhanjiang, primary P. taeda seed o rchard( PTA( p) ) in Y ingde, primary P. massoniana seed orchard( PMA ( p) ) in Ruyuan, respectively. The trialw as investigated for surv iva l rate, at the end of the plan ting year. And the he ight and diameter at breast height ( dbh) of indiv idual trees w ere measured at age 6. Then, preserv ing rate and ind iv idua l volumew ere ca lculated respective ly. The average surv ival rate o f 21 hybrid fam iliesw as 96. 2%, and preserv ing ratew as 87. 2%. Therew eremost sign ificant differences betw een all tested taxa for the ir increm en.t The order o f vo lume betw een taxa w as PEE PCH > PEE PCB > PCH ( p) > PMA ( p) > PCH ( op) > PEE ( op) > PEE ( i) > PEE ( p) > PCB ( p) > PCC ( p) >PEE ( o) > PTA ( p) . T en hybrid fam ilies w ere se lected in the tria l fo r the ir better g row th performance. The ir averagehe igh,t dbh and vo lume w ere 6. 35 m, 10. 85 cm and 0. 035 48 m3, respect ively. Their real average gains w ere59. 39%, 48. 76%, 134. 97%, 162. 23% and 172. 29% for volume, respective ly, compared to PMA ( p), PCH( p), PCB( p), PEE ( o) and PTA ( p).